How Efficient Are Solar Water Heaters?

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Intro

Solar power has gained so much popularity that everyone seems to be talking about it these days—and for good reason. It’s pretty hard not to be convinced by such an obviously beneficial concept. Essentially, the sun is supplying us with an endless stream of clean energy, and only a small percentage of us are taking advantage of it. As this energy-efficient lifestyle has become increasingly popular with a mainstream audience, prices of the once-expensive solar panels have dropped, and their usage is exponentially multiplying. From boats and cars to iPhone chargers and even trash compactors, there are countless ways to use solar energy to reduce the carbon footprint of our daily lives.

What might still be unknown to most is the fact that sunlight does not only convert to electricity, which is the case of solar panels. Another diffused option among homeowners is solar water heating, or solar thermal. It follows the same rules of traditional solar panels—secure on the roof, facing south—but has a different purpose. The energy of the sun is converted into heat rather than electricity, which can then be used for space or water heating. That means you can use it for your domestic hot water, your hot tub, or your swimming pool, to warm up your house, or a combination of the above.

What do they do (and don’t)?

One major thing to keep in mind is that solar water heaters will not turn your lights on—you will still need electricity to power the heater pump (and your home). The good news is that you will still be heating a big chunk of your hot water via a clean, renewable source, and saving money on your energy bills. It can provide around ⅓ of your hot water needs, and you will need one square meter of collector area on your roof for each person in the house. A system of that size will heat between 30 and 60 liters of water. Of course, if you want your home to be 100% clean, the best option would be a combination of photovoltaics and solar water heaters, so that the electricity you feed to the heaters is also green. However, using solar water heaters alone will significantly reduce your carbon footprint: you would save between 230 and 510 kg of carbon dioxide (CO2) every year. Moreover, these systems have very low maintenance costs and high durability, with a warranty between 5 and 10 years. Once the initial costs of installation are covered, your expenses will be limited to the small amount of electricity needed to power the pump that transfers the heat to the water, allowing you to save on the energy bill. Lastly, the solar thermal system works alongside your existing heating, boilers, heat pump, or biomass.

If you’re not ready to go full-on solar yet, solar water heating might be the perfect choice to get started. It requires a smaller investment (and depending on your region, you might be eligible for government incentives), and allows you to save money while making your house greener by reducing CO2 emissions. Plus, you’ll enjoy the comfort of a system that requires no attention once it’s installed: it’s noise-free and needs almost zero maintenance, so you’ll forget it’s even there. The only thing you will notice is the money you are saving.